Elite Air Check Valve by Hagen

I use these on all air pumps. Good way to safeguard from draining your tank in a power outage

I believe the extra cost of these are well worth it. They do not come apart as easily as cheaper alternatives and the spring mechanism seems to be a better design. I always buy these for new air pumps.

Out of the five I ordered, two did not let air pass when I first got them. I took a thin rod and used it to push up on the valve to unstick them. All five are working great now.

This is a must have if you use air pumps. It allows air to go into your tank with out the fear of water traveling back up the line (siphon effect) if the power were to go out. I use these on all my air pumps for peace of mind.